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(No Model.) 2 Sheets-Sheet 1.

N. s. KEITH.

ELECTRIC ARC LAMP. No. 281,698. Patented July 24, 1883.

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N. S. KEITH. ELECTRIC ARC LAMP. No. 281,698. Patented July 24, 1883.

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' BY/K'ZW ATTORNEY N. PETERS, llmlrlilhbgriphw. WuHngbn. n. C.

UNITE STATES PATENT OFFICE.

NATHANIEL S. KEITH, OF NEW YORK, N. Y.

ELECTRIC-ARC LAM-P.

SPECIFICATION. forming part of Letters Patent No. 281,698, dated July 24, 1883.

' Application fil ed October 18, 1882. (No model.)

To all whom it may concern Be it known that I, NATHANIEL S. KEITH, a citizen of the United States, and a resident of New York, in the -county of New York and State of New York, have invented certain new and useful Improvements in Electric Arc Lamps, of which the following is a specification.

My invention relates to electric lamps of the class in which a motor is employed for moving the carbon points toward each other to compensatev for the combustion which takes place at the arc, and is intended more particularly as an improvement upon lamps in which the motor employed is an electric mo tor.

The object of my invention is increased steadiness of the light, due to uniformity of the feed movement, simplicity of construction, and other desiderata incident to the employment of electric-arc lamps.

My invention consists in certain novel combinations of apparatus, that will be specified in the claims hereto annexed.

In the accompanying drawings like letters on all the figures refer to like parts.

Figure 1 is a general view of the mechanism of the lamp. Fig. 2 is a detail showing the cut-off apparatus, which is a part of the motor. Fig. 3 is a detail showing the parts which control the light when the arc may from any cause have an abnormally great resistance. Fig. 4 is a detail showinga part of the direct feeding worm and wheel, as well as the electromagnet which causes the worm to engage with or disengage from the wheel at proper times; and Fig. 5 is a diagram which shows the circuits and directions of currents in the lamp.

Ais the body or frame of the lamp, to which the various parts are attached, as shown.

B is a solenoid or axial magnet in the main or light circuit. It contains a movable core or piston, I), which is free to move vertically within the tube 2), and is suspended by the long helical spring b. The movement up or down of the piston communicates an oscillatory motion to the lever O bymeans of the pin z in the slot 0. This movement is communicated in its turn to the cutoff lever D, Figs. 1 and 2, by a pin, z, projecting from the end of lever G, and working in a slot, (1, in the lever D. The cut-off lever D, Fig. 2, is pivoted on the screw. (2, which is inserted in the hanger d of insulating materialsay wood or vulcanite. The other end has a small rod, y, attached to it, which may dip into the mercury E in the glass container E. The screw d (and so the lever 'D) is in electric connection with the main circuit on one side of the solenoid B. The mercury is in electric connection with the main circuit, but on the other side of the solenoid B. It is plain, then, that when a current flows in B the piston 12 is drawn downward, and so draws down the lever D, by reason of the pin z striking the bottom of the slot 01, until the small rod y comes into contact with the mercury E. This. contact completes a short circuit aroun d B, through which most of the current flows, and so decreases the magnetism of B that the spring I) raises the piston 12, the levers O and D, and the rod y out of the mercury, when the short circuit is broken and the full current flows in B, and the resulting attraction and movements take place, as just described. These are repeated as long as current flows.

It will be observed that by reason of the loose connection between the vibrating lever O and the cut-out or circuit-controlling lever D, formed by the pin 2 and slot (1, the shunt or cut-out circuit is not broken, so as to cause the re-energizing of the coil B, until the lever O completes its full upward movement, and the pin upon the end thereof strikes the top of the slot, and, similarly, that the current is not withdrawn from the coil until the lever has completed its full downward movement.

By this arrangement a full and extended movement of the lever is allowed, whereas if the circuit-controller or cut-out were of the ordinary kind, so that thelever would break the cut-off circuit at the moment it began to move upward, said lever would tend only to make rapid vibratory or trembling movement-s, i11- stead of the full and extended movements that are desirable.

To assist in the production of the action described, the leverD is preferably balanced by means of the adjustable counterpoise 1, so that it will tend to retain either of its two extreme positions until the lever G throws into the opposite extreme, and may also be adjusted to move with slight friction upon its point. This adaptability for retaining the position in which it is placed might be secured by other means obvious to skilled mechanics. A cutoff or circuit-controller constructed as above described may be applied with advantage to any elec tric motor in which a lever or similar mechanical device is kept in vibration through the alternate action ofa retractor and an electro-magnet, the flow of current to which latter is controlled by the action of a cutoif or circuitcloser worked by the movements of said lever.

The device as thus far described constitutes the electric motor by which the carboncarrier is operated; but I do not wish to be understood as limiting myself to this particular form of motor, nor to the particular location of it in the main circuit, although this is by far the preferable position for it.

Other forms of circuit-controller or cut-off might be used in place of that described, and said cut-off might be made to control the flow of current to the coil in other obvious manners, instead of by completing and breaking a short circuit around it. The cut-oil" or commutator as herein arranged, however, has the well-defined function of controlling the flow of current through the electro-magnet without rupturing the general circuit.

From the screw (1 to the lever D a flexible electric connection, 00, is made for the purpose of preventing sparks at the bearing during action, and the consequent roughening of the parts. The screw 0 serves to fasten the 0011- tainer E to the insulated base 0, and to act as a connection between the mercury and the wire of the circuit in well-known manner. The lever 0 serves to transmit the motion of the motor to the feeding mechanism of the lamp. The lever is pivoted on the shaft f, Figs. 1 and 4, and has three arms, the ofiice of one of which I have just described. The other two arms carry the pawls G and H, which swing from the pivots and h, respectively. It is plain thatthe direction of the rotation of the cog-wheel I and the shaft and worm f and F depends upon which one of the pawls is allowed to engage the teeth of the cog-wheel.

The mechanism which I have devised for the purpose of governing the engagement of said pawls with the wheel I will now proceed to describe.

K is a solenoid or axial magnet of high resistance, which is in a circuit derived around the are. It resembles in the construction of its tube and piston 70 the solenoid B.

Attached to the pi stonrod is the arm L, car rying the fingers Z Z, which may move freely alongside of the wheel I, between it and the lever O. The pawls rest against the outer edges of these fingers. The are of the outer edges of the fingersis described by a trifle longer radius than the radius of the wheel, so that when the fingers are concentrically placed in relation to the wheel neither pawl can engage with the teeth. Now, when the light is burning, the magnetism of K varies by the well-known rule, increasing and decreasing with corresponding changes in the length of the light-arc. The helical spring k is made adjustable as to its tension by the nut and screw "W, so that the normal position of the piston and arm can be changed at will. If the arc becomes too long, the piston-arm and fingers are drawn down, and the upper pawl, Z, as it vibrates to and fro, engages the teeth of the wheel successivelyin well-known manner, and moves it in proper direction to feed the can bons. As soon as the normal. length of arc is restored, the arm and finger will have resumed their position shown in Fig. l and the pawl H will become disengaged. If the arc become too short, the spring k will raise the pistonarm and fingers, so that the pawl G will engage the teeth of the wheel, so that thereby it will be moved in the contrary QllI'OOtlOII namely, that which causes the separation of the carbons.

The device just described constitutes a mechanical reversing device the function of which is merely to change the direction of movement of that portion of the mechanism.which gears with the carboncarrier, said mechanism being, however, driven at all times by a motor whose movement is uniformly the same. I do not, however, wish to be understood as limiting myself to the particular device herein de scribed, as other devices might be employed in its place, for converting a constant reciprocating movement into a rotary movement in either direction, said devices being controlled or set by an electro-magnet the strength of which is made to automatically vary in accordance with the resistance between the carbons.

Beside the lever G and the wheel I the shalt f has fastened upon it the worm F, Fig. 4. This worm is not shown in Fig. 1; but its position is obvious, as it engages with the wheel M, Figs. 1 and 4:. Rotation of the worm F communicates a rotary movement to the wheel M, and so to the shaft m and the pinion N. The post tive-carboircarrying rod 0 has parallel with its length a rack the teeth of which engage the teeth of the pinion N. Motion is communicated to the rod through this pinion and rack. One end of the shal'tf has its bearing in a post (not necessarily shown) like the posts a and o,- but the bearing of the other end is in the armature P of the electro-magnet Q, placed in the main circuit. hen no current, or a very weak one, flows in the coils of the elec tro-magnet Q, the armature I rests on the head of a stop-screw, p. In this position the worm F is free from the worm-wheel M, and the rod 0 may then be freely moved up or down, with only the small resistance of the shaft m in its bearings.

XVhen circuit is made and current flows, the armature P is magnetically drawn upward, and causes the engagement of the worm F and worm-wheel M. In this position no practicable force applied to the rod 0 will move it up or down, as the angle of incidence between worm and worm-wheel is sutlicientl y great to The carbon-carryprevent such movement.

IIO

ing rod, being so locked, becomes immovable except by the means described, and does not vary its position primarily, as in lamps in which the carbon-rod is held in equipoise by the differential action of weight or spring and a magnet.

. In Figs. 1 and 3, B is a lever, of metal, pivoted at 1' on the post 1;, which is in direct metallic and electric contact with the body of the lamp. S is a metallic stud, which is insulated from the body of the lamp, but is put in electrical connection with the main circuit at a point on the opposite side of the electro-magnet Q from that with which R is connected, as shown in the diagram Fig. 5 at q. Whenever the resistance of the are becomes abnormally increased above that necessary to cause the ordinary feedsuch as from failure to feed by sticking of mechanism-the piston 7c is drawn down so far that the end 1 of the arm L will bear upon the lever B until it raises the other end of said lever into contact with S, so making a shortcireuit around Q,.through which most of the current flows. This decreases the magnetism of Q, so that P drops and carries F away from M, and thereby allows the weighty carbon-carrying rod 0 to drop until the feeding and regulating mechanism above described can again operate. resistance of the are is decreased by this proximity, the arm L recedes from R, and R drops from contact with S, either by gravity or by a spring. If, then, the conditions be normal, the motor and mechanism will again move the carbons apart to restore the are. If not, the carbons will remain in contact by reason of y the weight of rod, and the current will flow through them.

Other constructions of circuit closer or 0011- troller might obviously be used in place of t R S, and the controller might be made to gov ern the admission or the Withdrawal of current from electro-magnet Q by other arrangements of circuits without departing from the spirit of the invention.

I have shown the shunt-circuit as originating at the body of the lamp A and short-circuiting the are, solenoid B, and electromagnet Q, as indicated by the broken line T, Fig. 5. It is plain that Q may be short-eircuited by connecting the lever B electrically with the circuit -Wire between the are and B, as shown by the broken line U, Fig. 5, or by making the connection between B and Q, as shown by the broken line V.

The drawings show and I have described only the working mechanism of the lamp. This may be mounted in the usual way in a case and a stand, as astanding lamp or as a hanging lamp.

Fig. 5 shows in diagram the circuits of the lamp. The current enters at the positive binding-post and divides, so that a small portion flows by the fine-wire circuit around K to the negative binding-post. The greater part flows to the carbons by way of the body of the lamp A, and thence to the motor B, and thence,

As the through the electro-magnet Q, to the negative binding-po'st. Intermittently portions of the current are diverted around B by means of D,

,g and E as has been described; also, at proper times portions of the current may be diverted around Q by either the circuits T, R, S, and Q, or U, R, S, and Q, or V, It, S, and Q, according to whichever of these circuits have been provided.

The operation of the lamp described is briefly as follows When the circuit is made and current flows, the reciprocating movement of the motor B commences and communicates an oscillatory movement to the lever O and a rotary movement to the wheel I, and, through the worm F and worm-wheel M, which have been brought into engagement by eleetro-magnet Q, an upward movement of the carbon-rod to form the arc. At the moment of making circuit so little current flows in the solenoid K that the spring It keeps the arm L and fingers Z Z at their uppermost limit, so that only the pawl G engages the teeth of the wheel I, thus producing the upward movement of the carbon carrier; but as the arc increases in length the magnetism of K increases, and finally draws K L and Z Z down, so as to disengage G. Both pawls are then held out of engagement with the wheel and ride backward and forward on the plates or fingers Z Z. The earbon-carrier remains stationary, being locked from movement at the worm and wormwheel. As the arc increases further in length the parts are still further drawn down until the pawl II engages the wheel, the pawl G remaining out of engagement, and so the feed takes places. If the resistance of the are in creases to an abnormal extent, the bar L is still further drawn downward, and t presses on R until contact with S takes place,which allows P to drop and disengage the worm F, so that the carbons come immediately into proximity or contact without breaking the circuit or current.

I do not limit myself to the particular location of what I have termed a reversing mechanism, as a device adapted to accomplish the same end might be placed at any suitable point in the train of wheels between the carbon-carrier and the motor, and made to reverse the direction of movement of the carrier by converting either a reciprocating or a continuous rotary movement in one direction into a movement in either direction. These are matters of mechanical detail admitting of many variations, all of which it would be useless to describe, the principle of the invention being in all the same, and consisting in the combination, with a constantly-acting motor for moving the carbon-carrier, of any suitable intermediate mechanical reversing mechanism controlled in accordance with changes of resistance at the arc, and acting to reverse the direction of movement of some member of the train connected to the carrier, so that said carrier may be made to move in either direction under the aeti on of the motor. It is also too apparent that other arrangements might be employed for disconnecting the carrier from the feedingtrain when the are becomes too long, so as to allow said carrier and its carbon to descend freely, and that the devices for effecting the disconnection might be operated or controlled by an electro-magnet placed in other portions of the general circuit and operating and controlled in other ways, the invention, so far as this portion of the lamp is concerned, consisting in bringing about the desired mechanical disconnection by means of an electro-magnet or equivalent device made to act for this purpose whenever the are becomes too long.

\Vhat I claim. as my invention is- 1. The combination, with a carbon-carrier, of a constantly-acting electro-magnetic motor in the main circuit, a derivedeireuit electromagnet, and mechanical reversing devices controlled by said derived circuit eleetro magnet.

2. of an electro -magnetic motor, the electromagnet of which is in the main circuit, a cut off or connnutator controlling a derived or shunt circuit around said magnet, and mechanical, reversing devices interposed between the motor and the carrier, as and for the purpose set forth.

3. The combination, substantially as described, of an electro-magnet, two simultaneously-1reeiprocating pawls kept in constant operation thereby, a toothed wheel, to which said pawls are applied, so as to tend to drive the same in opposite directions, mechanism for holding both of said pawls, or either singly, out of engagement with the wheel, a control ling electro-magnet in a derived circuit around the are for controlling said mechanism, and a gear-train connecting the wheel with the car hon-carrier, and suitably constructed to prevent the descent of the carrier by its own weight.

4. The combination, with a carbon-carrier, of a motor, mechanism for connecting and disconnecting said carrier with the motor, an electro-magnet in the main circuit controlling said mechanism, an electro-magnetin the derived circuit, and mechanism controlled thereby for reversing the direction of movement of the mechanism driven by the motor and con nected to the carrier.

5. The combination,with a carbon-carrier, of a controlling-train, an electro-magnet which, during normal operation of thelamp, holds two adjacent members of said train in engagement, a shunt-circuit closer for said electromagnet, and derived-circuit electro-magnet which acts to operate said circuit-closer upon an abnormal increase in the length of the are, thereby causing a disengagement of the members of the train, so as to allow the carbon to drop freely.

6. The combination, with a carbon-carrier, of a worm and worm-wheel in the controlling mechanism of said carrier, and an elcctra he combination, with a carbon-carrier,

magnet for causing the engagement and disengagement of said worm and wheel.

7. The combination, substantially as described, of a motor, a carbon-carrier, means for mechanically connecting or disconnecting said motor and carrier, interposed at or near the carrier, or at a point such that upon disconnection the carrier may drop freely, and a controlling electro-magnet by which the mechanical connection or disconnection is effected.

8. The combination of an electric motor, a carboncarrier, an intermediate train ol'wheels, one of the members of which, near the carboncarrier, is movable into and out of gear with the adjacent member, an electromagnet which operates said movable member, and an auto matic switch controlling the current passing to said electro-magnet, so as to cause the disconnection of the carbon-carrier from its con trolling-train, and a free descent of said carrier upon an abnormal. increase in the length of are.

9. The combination of the wheel I, gearing with the carbon-carrier, the lever C, carrying the two pawls, means for holding said pawls out of engagement with the wheel, controlled by a derived-circuit magnet, main-circuit electro-magnet, and an automatic circuit-breaker operated by the lever O, and controlling a shuntcireuit around the elcctromagnet, so as to keep the lever in constant vibration.

10. The combination of the carbon-carrier D, the worm and gear, the toothed wheel I, the constantly-vibrating arm 0, carrying the two pawls G H, the plates Z Z for holding said pawls out of engagement with the wheel, or allowing them to come into engagement therewith, and a derived-circuit electro-magnet for operating the lever upon which said plates are mounted.

11. The combination, with feed controlling or actuating mechanism for an electric lamp, of solenoid or coil 13, vibratory lever (3, cutoff circuit-closer D, and pin and slot .2" d, as and for the purpose described.

12. The combination of the electro-magnet and vibrating lever, the two pawls G H, adapted to act in opposite directions upon the toothed wheel I, the fingers Z Z, and a feed-controlling electro-magnet for operating said fingers so as to hold either or both of said pawls out of engagement with the wheel.

13. The combination, with the carbon-carrier, of the worm and gear, the clectro-magnet in the main circuit for bringing said worm and gear into engagement, the wheel I, reciprocating pawls G H, and the fingers Z 1, controlled by an electro-magnet in the derived circuit.

Signed at New York, in the county of New York and State of New York, this 2d day of October, A. D. 1882.

\Vitnesses:

Tnos. TooMnY,

G. TowNsnNn. 

